Over the past couple of weekends I have been building a solar oven inspired by the All American Sun Oven design. So far I have put around 20 working hours into the solar cooker and it’s coming together nicely.
Building the the box itself could be the most difficult part of this project because everything has to fit perfectly. Last week I put together the reflector panels which was fairly easy, and next week I’ll finish the box exterior.
The final part of this project will be putting the top together with all the hinges and accessories, and finally testing the solar cooker out.
Difficulty: This is the most difficult part of the whole project, but isn’t that hard with a little patience. Accurate measurements are important in this part of the project.
SHTF Value: Having as many ways to cook in a disaster is always a plus. There are not many options available for dehydrating or cooking food in an oven.
Cost: How much this costs really depends on the materials you use. The sheet metal is the most expensive part of the box, but can be substituted with wood.
Tools Needed: Drill – 3/16 Drill Bit – Skil Saw – Cutting Wheel (Fits Skil Saw) – Nail Gun (optional)
- 8ft 2 X 2 Wood (x3) $2 Each
- 3″ Screws (12) $8
- 3″ Bolt (x2) (with Washer and Nut) $3 Each
- 3/4″ Self Tapping Screws (#8) $10
- 2ft X 3ft Sheet Metal (x 2) $22 Each
- 8ft Aluminum 1/2″ Corner Guard $11 (Galvanized Steel is Cheaper)
- Rust-Oleum High Heat Spray Paint $4
You may have some of the items listed above which will reduce the cost, and you can also substitute lower cost items. For example Wood can be used instead of sheet metal.
Assembling the Frame
Other than cutting the angle at the top, this part is fairly straight forward. The base of the box is 17″ wide by 17″ in length. Basically just make a 17 x 17 square using the 2 x 2 wood.
The back (taller) corner posts should be cut to 10 1/2″ tall, and the front posts should be 6 1/2″ tall. This makes the inside dimensions slightly smaller than the All American Sun Oven but you can still use the accessories.
NOTE: I used a nail gun to hold the frame pieces in place before I added the more permanent screws. If you don’t have access to a nail gun you can skip this step and screw everything together. Just make sure everything is square before you do.
The Side Rails
As I show in the video, for the side rails I just cut them at 17″ and clamped them to the corner posts making sure they were flush with the top inside edges. I then marked my cut lines on the inside of the front and rear posts.
The Top (Front) Angle
When you connect the rails and posts you will notice that the top of the front posts are not flush with the side rails. to make the front post flush with the angled side rail I used a Skil saw to carefully trim it.
This is important because when you attach the top pieces later on everything needs to be flush. This isn’t important on the rear posts because they will be lower than the top facing. I’ll cover this more in the 4th video.
Front & Back Rails
For the front and back rails I cut them 14″ long and made sure they were flush with the outside edges of the posts.
After that I screwed everything into place more permanently. Be sure to drill screw holes in the wood before you add the screws. If you just drill straight into the wood it’s probably going to split on you.
When you start working on the inside box you are going to need wood to attach the edge guards and rack supports to. I added a 2 x 2 on each side of the posts, and one on each side for the rack supports.
For the rack support piece I measured 5 1/2″ in from the inside of the back corner post. (Not the extra wood in the corner, the actual corner post)
To get the correct angles for these I just cut a piece of wood a little longer than I needed, set it against the frame and drew a line where it needed to be cut.
Cutting the Sheet Metal
In order to get a perfectly straight line I used a straight edge and cutting wheel for my Skil saw. The cutting wheel was around $6 at the hardware store and worked pretty well.
The most important parts of this step are making sure the sheet metal doesn’t move, and you take it slow with the cutting wheel.
I used 1 of the 2′ x 3′ pieces of sheet metal to cut out the middle section of the interior box. I wanted 1 full piece to go from the front, along the bottom, and up the back side. I also wanted it to overlap the top of the box by 1 1/2″.
The interior dimensions of the box are 10 1/2″ high (back), 6″ high (front), 14″ (bottom) and 14″ wide. With 3″ added (1 1/2″ on front and back) for overlapping the top I cut this piece 14″ wide and 33 1/2″ long.
For the side panels the inside box dimensions are 14″ (bottom) x 12″ (back) x 8″ (front). These measurements include the 1 1/2″ overlap on the top.
Bending the Sheet Metal
When it comes to bending the sheet metal to fit the inside of the box you can either use a vice, or clamps and a straight edge if you don’t have one. You can start the bend by hand, and then finish it off with a rubber mallet.
You will need 2 bends to form the base of the box and the overlap folds at the top. for the sides you just need to bend the overlap portions.
Installing Rack Supports
Because I want to use the accessories that come with the All American Sun Oven I needed to install the supports to hold the Sun Oven rack. For this I used 3″ bolts with a washer.
I drilled these hole from the inside out with the sheet metal in place. On the outside (wood side) I drilled a larger hole (the size of the bolt head) slightly into the wood so it would fit flush with the outside of the box. In the video I show exactly what I’m talking about.
Attaching the Corner Molding
I chose to use 3/4″ aluminum corner trim for this box, but you could also use some less expensive wood trim. I wanted to seal the interior of the box as much as possible without using glue or caulking that might give off toxic fumes.
I cut 6 pieces to fit the open seams of the box and used the smallest self tapping screws as possible. For those who don’t know, a self tapping screw allows you to screw into metal without having to use a drill bit.
Painting The Interior Box
The final part of this part of the project was painting the inside of the box. For this I used Rust-Oleum High Heat Spray Paint. This paint was designed for use on outdoor grills and will withstand the heat in this box and is non toxic once dried.
I have seen white a few DIY solar ovens that use tin foil or are unpainted, so this step is really up to you. My thinking was that black absorbs heat better than a reflective interior.
Although it may be unnecessary I am also letting this box sit in the sun for a few days to let the paint bake off any toxins or smells. Again, not sure how necessary this is, but it can’t hurt right?
Coming Up Next…
The next video and tutorial in this DIY solar oven series is putting the insulation and case on the solar oven. After that We will be putting the top, the accessories, and finally testing this sucker out.
You can view the next tutorial as well as all the other steps using the links below.